The prior art is replete with thermal switches in which a contact is normally supported by a fusible pellet to make contact between electrical leads and is biased by a compression spring to break the electrical contact upon melting of the fusible pellet. Such switches are, for example, disclosed in U.S. Pat. Nos. 3,180,958; 3,281,559; 3,291,945; 3,519,972; 3,820,050; 3,956,725; and 4,068,204. In the thermal switches of U.S. Pat. Nos. 3,291,945; 3,820,050; and 3,956,725 the contact element contacts both electrical leads to complete the circuit between them.